U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 9459016 PUBLICATION DATE: 04/13/2005 Name: MITROFANIA ISLAND AK NOAA Chart: NONE Latitude: 55° 53.4' N ( 55.89000) USGS Quad: STEPOVAC BAY (D-3) Longitude: 158° 49.2' W (-158.82000) To reach the bench marks from the harbor in Sand Point, AK, proceed NE 20.5 km (11 nm) to the north point of Korovin Island, then proceed ENE 46 km (25 nm) to the SE point of Kupreanof Point, then proceed NE 60 km (32 nm) to a west facing cove on the north side of Mitrofania Island. The bench marks are located in the NE corner of the cove. The tide gauge orifices were located approximately 110 m offshore. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 9016 E 2004 DESIGNATION: 945 9016 E MONUMENTATION: Tidal Station disk VM#: 17731 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBBH57 LATITUDE: 55° 53.3' N ( 55.88830) LONGITUDE: 158° 49.1' W (-158.81800) The primary bench mark is located 249 m (817 ft) ESE (117 magnetic) from bench mark 9016 A 2004, 101 m (331 ft) SE (141 magnetic) from bench mark 9016 D 2004, 31 m (102 ft) south (166 magnetic) from a meandering stream in the grass and alder flats, 30 m (98 ft) SW (221 magnetic) from the base of a grassy hill below the most prominent rock peak in the NE corner of the cove, and 17.0 m (55.8 ft) ENE (78 magnetic) from the top edge of the gravel beach. The datum point is the top of a stainless steel rod set 0.01 m (0.03 ft) below grade, driven 6.7 m (22 ft) to refusal, marked with a punch and enclosed in an 8-inch NGS logo cap.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 9459016 PUBLICATION DATE: 04/13/2005 Name: MITROFANIA ISLAND AK NOAA Chart: NONE Latitude: 55° 53.4' N ( 55.89000) USGS Quad: STEPOVAC BAY (D-3) Longitude: 158° 49.2' W (-158.82000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9016 A 2004 DESIGNATION: 945 9016 A MONUMENTATION: Tidal Station disk VM#: 17727 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 55° 53.4' N ( 55.89000) LONGITUDE: 158° 49.3' W (-158.82200) The bench mark is a disk set flush in a rock outcrop, 249 m (817 ft) WNW (297 magnetic) from bench mark 9016 E 2004, 46 m (150 ft) west (264 magnetic) from bench mark 9016 B 2004, 4.3 m (14.1 ft) NE (42 magnetic) from a triangular pointed rock 1 m (3 ft) high, 0.6 m (2.0 ft) from the edge of the vegetation and 0.5 m (1.6 ft) below the vegetation. BENCH MARK STAMPING: 9016 B 2004 DESIGNATION: 945 9016 B MONUMENTATION: Tidal Station disk VM#: 17728 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 55° 53.4' N ( 55.89000) LONGITUDE: 158° 49.3' W (-158.82200) The bench mark is a disk set flush in a rock outcrop, 67 m (220 ft) west (268 magnetic) from bench mark 9016 C 2004, 46 m (150 ft) east (84 magnetic) from bench mark 9016 A 2004, 10 m (33 ft) sloped SSE (155 magnetic) from top of highest point on rock outcrop, 9 m (30 ft) ESE (115 magnetic) from the end of the arm on the rock outcrop jutting westward, 2.6 m (8.5 ft) SW (214 magnetic) from the grass covered top of the arm of the rock outcrop jutting eastward, and 2.5 m (8.2 ft) below the grass covered top of the eastward arm of the rock outcrop.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 9459016 PUBLICATION DATE: 04/13/2005 Name: MITROFANIA ISLAND AK NOAA Chart: NONE Latitude: 55° 53.4' N ( 55.89000) USGS Quad: STEPOVAC BAY (D-3) Longitude: 158° 49.2' W (-158.82000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9016 C 2004 DESIGNATION: 945 9016 C MONUMENTATION: Tidal Station disk VM#: 17729 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 55° 53.4' N ( 55.89000) LONGITUDE: 158° 49.2' W (-158.82000) The bench mark is a disk set flush in a sandy rock outcrop at the top of the beach underneath an alder tree, 67 m (220 ft) east (86 magnetic) from bench mark 9016 B 2004, 35 m (115 ft) NW from bench mark 9016 D 2004, 27 m (88 ft) east (101 magnetic) from a 1.6 m (5.2 ft) high dark grey rock on the gravel beach, 18.9 m (62.0 ft) NNW (330 magnetic) from a 4 m (13 ft) high slightly pointed rock on the gravel beach, 0.9 m (3.0 ft) south from the edge of the vegetation, 0.5 m (1.6 ft) below the vegetation, and 0.5 m (1.6 ft) above the gravel beach.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 9459016 PUBLICATION DATE: 04/13/2005 Name: MITROFANIA ISLAND AK NOAA Chart: NONE Latitude: 55° 53.4' N ( 55.89000) USGS Quad: STEPOVAC BAY (D-3) Longitude: 158° 49.2' W (-158.82000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9016 D 2004 DESIGNATION: 945 9016 D MONUMENTATION: Tidal Station disk VM#: 17730 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Rock outcrop OPUS PID: LATITUDE: 55° 53.4' N ( 55.89000) LONGITUDE: 158° 49.2' W (-158.82000) The bench mark is a disk set flush in a low sedimentary rock outcrop, 101 m (331 ft) NW (321 magnetic) from bench mark 9016 E 2004, 35 m (115 ft) SE from bench mark 9016 C 2004, 15.4 m (50.5 ft) NNE (21 magnetic) from a 5 m (16 ft) high boulder on the gravel beach, 14.6 m (47.9 ft) east (96 magnetic) from the seaward edge of a 4 m (13 ft) high rock on the beach, 8.8 m (28.9 ft) ESE (102 magnetic) from a rock ledge at the base of a grass slope 1.4 m (4.6 ft) above the gravel beach, and 1.0 m (3.3 ft) seaward from the vertical rock ledge at the base of the grass slope.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 9459016 PUBLICATION DATE: 04/13/2005 Name: MITROFANIA ISLAND AK NOAA Chart: NONE Latitude: 55° 53.4' N ( 55.89000) USGS Quad: STEPOVAC BAY (D-3) Longitude: 158° 49.2' W (-158.82000) T I D A L D A T U M S Tidal datums at MITROFANIA ISLAND based on: LENGTH OF SERIES: 4 MONTHS TIME PERIOD: May 2004 - August 2004 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 9459450 SAND POINT, POPOF ISLAND Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 2.356 MEAN HIGH WATER MHW = 2.121 MEAN TIDE LEVEL MTL = 1.266 MEAN SEA LEVEL MSL = 1.248 MEAN LOW WATER MLW = 0.410 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 9016 E 2004 4.446 2.325 9016 A 2004 3.671 1.550 9016 B 2004 2.982 0.861 9016 C 2004 3.537 1.416 9016 D 2004 3.319 1.198
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 9459016 PUBLICATION DATE: 04/13/2005 Name: MITROFANIA ISLAND AK NOAA Chart: NONE Latitude: 55° 53.4' N ( 55.89000) USGS Quad: STEPOVAC BAY (D-3) Longitude: 158° 49.2' W (-158.82000) D E F I N I T I O N S Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal Datum Epoch. It pertains to local mean sea level and should not be confused with the fixed datums of North American Vertical Datum of 1988 (NAVD88). NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum constraint adjustment of Canadian/Mexican/United States leveling observations. Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as the single initial constraint. NAVD88 replaces NGVD29 as the national standard geodetic reference for heights. Bench mark elevations relative to NAVD88 are available from NGS through the World Wide Web at National Geodetic Survey. NGVD29 is a fixed datum adopted as a national standard geodetic reference for heights but is now considered superseded. NGVD29 is sometimes referred to as Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological Survey Topographic Quads. NGVD29 was originally derived from a general adjustment of the first-order leveling networks of the U.S. and Canada after holding mean sea level observed at 26 long term tide stations as fixed. Numerous local and wide-spread adjustments have been made since establishment in 1929. Bench mark elevations relative to NGVD29 are available from the National Geodetic Survey (NGS) data base via the World Wide Web at National Geodetic Survey. NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to local MSL and other tidal datums may not be consistent from one location to another. The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique identifiers for bench marks in the tidal and geodetic databases, respectively. Each bench mark in either database has a single, unique VM# and/or PID# assigned. Where both VM# and PID# are indicated, both tidal and geodetic elevations are available for the bench mark listed. The NGS's Integrated Data Base (IDB PID) provides geodetic datum based on traditionally leveled and bluebooked ties to the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/. The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/. The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred to MLLW only when two or more of the bench marks listed have NAVD88 elevations. The NAVD88 elevation relationship shown in the table is derived from an average of several bench mark elevations relative to tide station datum. As a result of this averaging, NAVD88 bench mark elevations computed indirectly from the tidal datums elevation table may differ slightly from NAVD88 elevations listed for each bench mark in the NGS database.